Automatic transmission



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AUTOMATIC TRANSMISSION l0 Sheets-Sheet 10 Filed June 18, 1945 PatentedDec. 9, 1,952

AUTOMATIC TRANSMISSION Palmer Orr and George E.Flinn, Muncie, Ind.,

assignors to Borg-Warner Corporation, Chicago, Ill., a corporation ofIllinois Application `lune 18, 1945, Serial No. 599,99

Our invention relates to transmissions for automotive vehicles and moreparticularly to control mechanisms for such transmissions.

A Well-known type of automotive transmission ordinarily comprises aplurality of gear trains, at least several of which may be completed bymeans of jaw clutches, and also a primary friction clutch disposedbetween the drive shaft for the gear trains and an engine for thevehicle. It is an object of our invention to provide mechanism for powershifting a gear train completing jaw clutch in such a transmission andfor automatically opening the friction clutch between the engine andtransmission while the shift is being made. It is contemplated that thefriction clutch shall be opened just prior to a shifting into or out ofmesh of the jaw clutch and shall be closed just after the jaw clutch hascompleted its shifting movement.

For the accomplishment of such objects, it is a further more specificobject of our invention to provide a lost motion electric switchconnected with a power cylinder, with the arrangement being such thatthe power cylinder functions to shift a jaw clutch and the switch is putinto a changed electrical condition while the power cylinder isoperative to make a shift of the jaw clutch. It is contemplated that theelectric switch shall be connected with power mechanism for disengagingthe primary clutch so that the primary clutch is disengaged while theshift is being made.

It is a further object of our invention to utilize this power mechanism,for shifting a jaw clutch and disengaging a primary clutch, withtransmission ccntrol mechanism which is under the control of theaccelerator for the automotive vehicle so that a shift is made in thetransmission by moving the accelerator to one of the limits of itsmovement. It is accordingly an object of the invention to provideconnecting means between the power cylinder for shifting the jaw clutchand the accelerator so that the power cylinder is operative when theaccelerator is moved to one of the limits of its movement.

The invention disclosed and claimed in this application is similar insome respects to the inventions disclosed and claimed in the applicationof John M. Simpson, George E. Flinn, and Carl W. Osborne, Serial No.599,992, filed June 18, 1945, and the application of George E. Flinn,Serial No. 599,993, filed June 19, 1945.

The invention consists of the novel constructions, arrangements anddevices to be hereinafter described and claimed for carrying Out theabove 47 Claims. (Cl.y 192-.092)

stated objects and the such other objects as will appear from thefollowing description of certain preferred embodiments illustrated inthe accompanying drawings, wherein: j

Fig. l is a longitudinal sectional view of an automotive transmissionconnected with a vehicle engine; I

Fig. 2 is a diagrammatic illustration of the control mechanism for thetransmisison shown in Fig. 1, the ignition switch for the vehicle Abeingopen and the accelerator being in closed throttle position; A r

Fig. 3 is a view similar to Fig. 2 butwith the ignition switch beingclosed and with the vehicle engine being in operation to supply a vacuumFig. 4 is a view similar to Fig. 3 but with the accelerator beingpartially depressed, the transmission itself having been preliminarilyconditioned for low speed forward drive;

Fig. 5 is a View similar to Fig. 4 but with the vehicle travelling aboveve miles per hour and with the accelerator released to initiate a shiftof the transmission from low to second speed ratios;

Fig. 6 is a view similar to Fig. 5 but after a shift from first speedratio to second speed ratio has taken place, with the accelerator stillreleased;

Fig. 7 is a view similar to Fig. 6 but with the accelerator depressedafter the shift from first to second speed ratios has taken place;

Fig. 8 is a view similar to Fig. '7 but with-the vehicle travellingabove ten miles per hour and with the accelerator released to cause ashift from second speed ratio to high speed ratio;

Fig. 9 is a view similar to Fig. 8 but with the shift to high speedratio completed and with the accelerator depressedto cause a downshiftfrom third speed ratio to second speed ratio;

Fig. 10 is a diagrammatic illustration of.a modified control mechanismfor the transmission shown in Fig. 1, with the mechanism being shownwith the Vehicle speed being above ten miles per hour and with theaccelerator being in open throttle or kickdown position; and

Fig. 11 is a diagrammatic illustration of one of the relays used in thetransmission control mechanisms illustrated in Figs. 2 to 10.

Like characters of reference designate like parts in the several views.

Referring now in particular to Fig. 1 of the drawings, the illustratedtransmission is one particularly suitable for use in an automotive ve'-hicle and comprises a drive shaft l0 and a driven shaft I I The driveshaft l0 is adapted to be driven by means of the engine I2 ofthe vehiclewhich is the ordinary internal combustion engine usually used in suchVehicles. The shaft I is connected with the engine by means of afriction clutch I3 and a hydraulic coupling I4. The hydraulic couplingI4 may be of any suitable well-known construction and comprises animpeller element I5 and a rotor element I8. The element I5 is driven bythe motor I2 and fluid in the device I4 functions on such driving of theimpeller element to drive the rotor element I5 of the device.

The clutch I3 comprises a driving element I1 and a driven element I8.The driving element is connected with the rotor I6 of the couplingdevice I4 and the driven clutch element I8 is connected with the driveshaft I0 of the transmission. The driven clutch element I8 is clampedbetween a pressure plate I9 and the driving element I1 of the clutch.Radially extending clutch levers act on pressure plate I9 by means ofstruts 2I, and these levers are pivotally mounted on studs 22 which arefixed with respect to a clutch cover 23 which rotates with the drivingelement I1. Springs 24 are disposed between the cover 23 and thepressure plate I9 for yieldingly holding the pressure plate against thedriven element I8 for maintaining the clutch engaged. A collar 25 isslidably disposed on a housing portion 26 for the transmission, and thiscollar is disposed to act against the clutch levers 20 to move thepressure plate I9 rearwardly by means of the struts 2I to disengage theclutch. The collar 25 is acted on by means of a release lever 21 fixedon a shaft 28.

The drive shaft IG is journaled in the housing for the transmission bymeans of a roller bearing 36, and the driven shaft II is journaled inthe housing 35 by means of the roller bearing 31. The shaft II ispiloted in the shaft I0 by means of rollers 38, as shown. The driveshaft Il is formed with a spur gear 39, and this gear is in mesh with agear of a gear cluster 4I. A countershaft 42 is provided in the housing35, and the gear cluster 4I is rotatably disposed on the countershaft. Agear 43 is rotatably disposed on the driven shaft I I and is in meshwith a gear 44 on the gear cluster 4|. Another gear 45 is disposed onthe driven shaft II and is supported with respect to the shaft by meansof a hub 48 splined on the shaft and a one-way roller clutch 41. Theroller clutch may be of the ordinary type comprising rollers disposedbetween opposite cam surfaces, and the clutch is such that it willengage when the gear 45 is driven in the forward direction for therebydriving the shaft I I. The gear cluster 4I also comprises gears 48 and49 which are adapted to cooperate with the gear 45. The gear 49 is inmesh with an idler gear 5U which is rotatably supported by any suitablemeans with respect to the housing 35. The gear 45 depending on theposition to which it is moved on the shaft II may mesh either with thegear 48 or with the idler gear 50. An element 5I having external teeth52 is splined on the shaft II, and the gear 45 is provided with internalteeth 53. The teeth 53 are adapted to mesh with the teeth 52 when thegear 45 is moved rearwardly of the transmission to mesh with the idlergear whereby the one-way clutch 41 is rendered ineffective.

A double positive type clutch 54 is provided for connecting either theshaft I0 or the gear 43 with the shaft II. This clutch comprises aninternally toothed collar 55 slidably and nonrotatably disposed on a hub56 which is splined to shaft II. The shaft ID is provided with teeth 51and the gear 43 is provided with teeth 58 which are adapted to be meshedwith the internal teeth of the collar 55 depending on the direction inwhich the collar is moved. A synchronizer ring 59 of any suitablewell-known construction is disposed on each side of the collar 55 on theshaft I0 and on the gear 43 for synchronizing the speed of the collarwith either the teeth 51 or the teeth 58 before engagement of the collarwith the teeth. A yoke 60 is provided which fits in a groove fromed inthe collar 55 for shifting the collar as will be hereinafter described.The transmission is also controlled by means of a governor which will behereinafter described,yand the governor is driven from the driven shaftII by means of gearing 6I.

The illustrated transmission provides three speed ratios in forwarddrive and one speed ratio in reverse drive. When the gear 45 is shiftedinto mesh with the gear 48, the transmission is conditioned for lowspeed forward drive and the drive is from the shaft I!! through thegears 39 and 40, the gear cluster 4I, the gears 48 and 45, the one-wayclutch 41 and the hub 46 to the shaft II. The shaft I0 is driven fromthe engine I2 through the coupling I4 and clutch I3 as will beunderstood. Second speed forward drive is provided by shifting thecollar 55 to mesh with the teeth 58. The drive is then from the shaft I0through the gears 39 and 40, the gear cluster 4I, the gears v44 and 43,the teeth 58, the collar 55 and the hub'55 to the shaft I I. High orthird speed forward is provided by shifting the collar 55 to mesh withthe teeth 51. The drive is then from the shaft I0 through the teeth 51,collar 55 and hub 56 to the shaft II. The gear 45 may be allowed toremain in mesh with the gear 48 for both second and high speeds forward,and the clutch 41 overruns. For reverse drive the gear 45 is shiftedinto mesh with the idler gear 55, with the collar 55 being in itsneutral position in which it is shown in Fig. 1. The drive is then fromthe shaft I0 through the gears 39 and 40, the gear cluster 4I, the gears49, 5D and 45, the teeth 53 and 52, and the element 5I to the shaft II.The overrunning clutch 41 would overrun for this direction of drive, andthe teeth 53 and 52 and the element 5I are thus necessary for reversedrive.

The mechanism for controlling the transmission shown in Fig. 1 comprisesin general (see Fig, 2) an ignition switch 65 connected with the batteryG5 of the vehicle, a forward conditioning switch 61, second to highspeed ratio conditioning relay 68, a rst to second speed ratioconditioning relay B9, a high ratio conditioning relay 19, a coastswitch 1I, an electric governor 12, an accelerator switch unit 13actuated by the accelerator 14 of the vehicle, a throttle 15 for theengine I2 and having a butterfly valve 16 con.- nected by linkage 11with the accelerator 14 and having another butterfly valve 18 actuatedby an electric solenoid 19, an accelerator controlled clutch control orengaging valve 88, a vaccum shut-off valve 8|, a one-way vacuum valve82,

an electrically controlled vacuum valve 83, a vacuum motor 84 for theclutch I3I a vacuum motor 85 connected with a lever and a switchassembly 86 for shifting the collar 55, an electrically operated vacuumvalve 81 for the motor 85 and another electrically operated vacuum valve88 for the motor 85.

The battery 66 on one terminal is grounded in accordance with standardpractice, and the battery has its other terminal connected with theignition switch B5. A fuse or other overload de- 5 vice-95 .is connectedin series with the switch 65, and the switch E1 is connected in serieswith the fuse. The relay 68 comprises a relay winding 90, contacts 91,contacts 98 and contacts 90. As will be noted, the winding 9B and thecontacts 99 are connected in series with the switch 61.

The relay 69 comprises a relay winding |00, contacts and contacts |02.One of the contacts |02 and one end of the winding |00 are connectedwith the switch 61, and the other of the contacts |02 is connected withone of the contacts 91, as shown. The other end of the winding |00 isconnected with one of the contacts I0 The relay 10 comprises a relaywinding |03, contacts |04 and other contacts |05. One end of thewindingii is connected with one of the relay contacts |02 and one of thecontacts |05 is connected with an end of the relay winding 96 as shown.One of the contacts |04 is connected with one end of the winding |03 andthe other contact is grounded.

The relays 68, 99 and 10 may be of any suitable construction. The relay08 is shown in some detail in Fig. 11 and comprises a core 68a on whichthe winding 95 is disposed. A pivotally mounted armature 601) isdisposed at one end of the core and carries a Contact 01, a contact 98and a contact 99. The other contacts 91, 98 and 99 are stationary, andthe contacts are made and broken withv movement of the armature as isapparent. The relays 69 and 10 are similar in construction to the relay9S with the contacts 0| and |04 and the contacts |02 and |05corresponding to the contacts 08 and 99, respectively. In the relays 59and 10 there are no contacts corresponding to the contacts 91.

The coast switch 1| comprises contacts |00 and contacts |01 and aswitcharm |08 adapted to bridge either the contacts |06 or |01. One of thecontacts |00 is connected with one of the relay contacts |05, as shown.One of the contacts |01 is connected with the relay winding |00, and theother is grounded. The governor 'i2 may be of any suitable type vand isdriven from the driven shaft I by the gearing 0|, and the governorcomprises contacts |09, H0, and ||2. When the driven shaft is at rest,the contacts |09 are closed while the other of the governor contacts areopen, as shown in Fig. 2. At approximately a speed of the shaftcorresponding to ve miles per hour speed of the vehicle, the contacts|09 open and the contacts H0 close. At a speed of the shaftcorrespending to approximately ten miles per hour, the contacts close,and the contacts ||2 close at approximately forty miles per hour speedof the vehicle. It will be understood that the contacts ||0 remainclosed at all speeds above ve miles per hour, the contacts i remainclosed at all speeds above ten miles per hour and the contacts ||2remain closed at all speeds above forty miles per hour. One of each ofthe sets of contacts |09, H9, Hi and ||2 is grounded as shown. The otherof the contacts ||0 is connected with one of the contacts |0| and theother of the contacts ||2 is connected with one of the contacts 98 'asshown.

The accelerator switch 13 comprises contacts H3, contacts H4, -contactsland contacts ||6, an accelerator plunger ||1, and switch arms I8, ||9and |20. A spring |2| is provided between the arm ||9 and a stationarypart for yieldingly holding the plunger |1 and accelerator 14 in theclosed throttle positions of these parts in which they are shown in Fig.2. A spring |22 is provided for yieldingly holding'the switch arm |20 inits position bridging the contacts I6. One of the contacts 3 isconnected with a contact ||6 and also with one of the contacts I2 of thegovernor. The other contact ||3 is connected with one of the contacts|06 of the coast switch 1|. One of the contacts |i4 is connected withone of the contacts ||0 of the governor, and the other of the contacts|4 is connected with o-ne of the contacts |01 of the coast switch. Oneof the contacts l5 is connected with the winding |03 of the relay 10,and the other contact ||5 is grounded. One of the contacts ||6 isconnected with one of the contacts I3 as described above, and the othercontact 6 is connected with one of the governor contacts The butteryvalve 1B in the throttle 15 oithe engine 2 is connected by means'of aforked lever |23 with the armature |24 of the solenoid 19. The solenoid19 when energized functions to turn the lever and thereby move the valve18 whereby to substantially close lthe throttle 15 and allow the engine|2 to operate only at idling speed. One end of the solenoid is connectedwith the battery 55 through the switch 65 and fuse 95 as shown.

The valve 8| comprises an electric solenoid |25 for operating the valve,and this solenoid has one end connected to the battery through the fuseand the ignition switch and its other end is connected with one of thegovernor contacts |09. The electrically operated valve 83 comprises asolenoid |29, and one end of this solenoid also is connected with thebattery through the fuse and ignition switch.

The electrically operated valve 81 comprises a solenoid |21 which hasone end connected with one of the contacts 91 of the relay 60. The valve88 comprises an electric solenoid |28, and one end of this solenoid isconnected with one of the contacts 99 of the relay 68.

The suction motor comprises two holding coils |29 and |39. One end ofeach of the holding coils is grounded as shown, and the end of the -coil|29 is connected with one end of the solenoid |21 and the other end ofthe coil |30 is connected with one end of the solenoid |28, as shown.

The lever and switch assembly 85 comprises the switch |3| havingcontacts |32 and a switch arm |33. The two contacts are connected withone end of the throttle closing solenoid 19 and also with one end of thesolenoid |29 of the valve 83. The switch arm |33 is grounded as shown.

The linkage mechanism 11 -coupling the accelcrater pedal 14 and thebutterfly valve 15 of the throttle 15 together comprises a lever |40connected by means of a link |4| with the pedal 14, another lever |42connected by means or a link 43 with the lever |49, a bell crank lever|44 connected by a link |45 with the lever |42 and by a link |46 with alever |41 which is connected with the valve 19. The lever |42 is pivotedat |48 and has a spring 49 acting on its end connected with the link|45. The lever |42 is formed with a portion 50 which is adapted tocooperate with the lever |40 as will be hereinafter described.

When the accelerator 14 is depressed, that is, when it is moved in acounterclockwise direction as seen in Fig. 2, the link |4| is moved tothe right as seen -in this figure and as indicated by the arrow, and thelever |40 is moved in a counterclockwise direction about its connectionwith the link |43 until it contacts the portion |50 of the lever |42. Aclearance ordinarily exists between the upper end of the lever |40 andthe part |50 of the lever |42 before the accelerator has beendepressedrfor'purposes which will hereinafter be described. After thelever |40 has contacted the portion |50, both the levers |40 and |42thereafter move together about the pivot |48 in a counterclockwisedirection against the action of the spring |49, and the movement of thelever |42 through the links |45 and |46 and the bell crank lever |44moves the buttery valve 16 to open the throttle 15. The butterfly valve10 is the ordinary throttle opening valve ordinarily found in thethrottle of an internal combustion engine, and it is opened by adepressing of the associated accelerator as in ordinary installations.

The clutch engaging valve 86 is actuated by the accelerator 14 and theaccelerator linkage 11. The valve comprises a valve block having apassage therein which forms a part of a vacuum conduit |52, and theblock is provided with a chamber |53 therein which is connected with aconduit |54. A valve piston |55 is disposed in a cylindrical cavity inthe valve block |5| and this cavity is connected by means of openings|55 with the chamber |53. The piston |55 is provided with lands |51 and|58 tting in the cavity for the piston, and the piston is hollow asshown. A plunger |59 extends through the valve body |5I, and the plungeris provided with a stop |60 on an end thereof for limiting its movement.A passage IGI is provided in the valve body, and the plunger |59 isprovided with a groove |62 which completes the passage from the chamber|53 to the atmosphere when the plunger |59 is positioned with its stop|60 against the valve block |5|. The plunger |59 is connected by meansof o effective on the diaphragm and the motor is connected by means of aconduit |61 with the chamber |53 in the valve block |5|. The plunger|59, the valve piston |55, and the plunger |54 are connected together bymeans of a floating lever |53. The connection of the lever |68 with thepiston 55 is a simple pivotal connection While the connections of thelever |68 with the plungers |59 and |64 are pin and slot connections asshown.

The conduit |52 is connected to a vacuum conduit |69 by means of thevalves 8| and |52 and a conduit |15. The conduit |69 is connected withthe manifold of the engine I2 or any other suitaole source of vacuum.The valve 82 is a one way valve of any suitable construction whichallows vacuum to be introduced into the conduit but does not allowatmospheric pressure to enter the conduit |10 if the vacuum in theconduit |69 momentarily decreases, such as to atmosplieric pressure. Thevalve 8| is a two position valve comprising a valve piston |1| which isactuated by the solenoid |25. The valve 8| has an atmospheric port 8|ain its casing through which air may pass as will be described. When thesolenoid is deenergized, in which condition it is shown in Fig. 2, thepiston |1| blocks the conduit |10 and permits atmospheric pressure toenter the conduit |52 through the port 8|a. When the solenoid |25 isenergized, the piston |1| is drawn upwardly to close the port Sla to theatmosphere and to connect the conduits |10 and fio 8. |52 for therebycausing vacuum to be applied to the valve 80.

The chamber |53 in the valve body |5| is connected to the valve 83 bymeans of the conduit |54. The valve 83 is also connected with the vacuummotor 34 by means of a conduit |12, and the valve is connected with thevacuum conduit |69 by means of a conduit |13. The valve 83 is atwo-position valve and comprises a valve piston |14 acted on by thesolenoid |26. When the solenoid |26 is deenergized, the valve piston |14is in its position as shown in Fig. 2. In this position the valve pistonblocks the conduit |13, and the valve connects the conduits |54 and |12.When the s-olenoid |26 is energized, the valve piston |14 is raised soas to block the conduit |54 and to connect the conduits |13 and |12. Thevacuum motor 34 comprises a diaphragm |15 which is connected by means ofa link |16 with a lever |11 that is xed to the rock shaft 28 for theclutch actuating lever 21.

The valve functions to cause engagement of the clutch I3 in accordancewith the wishes of the driver of the vehicle as expressed through theaccelerator 14, that is, the rate of engagement of the clutch I3 isunder the control of the accelerator 14. rThe vacuum motor 84 in itscondition as shown in Fig. 2 has no vacuum applied to it, and the clutch|3 is engaged. If vacuum is applied to the motor 84 through the conduit|12, the diaphragm |15 of the motor operates by means of the link |16,the levers |11, 21 and 20 and the collar 25 to disengage the clutch |3against the action of the clutch springs 24. If the solenoid |26 of thevalve 83 is energized, the valve piston |14 is raised and vacuum isapplied to the motor 84 through the conduits |13 and |12 for disengagingthe clutch. If the solenoid |26 of the Valve 83 is deenergized to blockthe conduit |13, the vacuum for disengaging the clutch |13 must comethrough the conduits |52 and |54, When the solenoid |25 of the valve 8|is energized, the valve 8| functions to connect the conduit |52 to theconduit |69 by means of the conduit |10, and the valve 80 may functionto connect the motor 84 with the conduit |52, when the accelerator isdepressed as will be described, through the conduits |54 and |12.

The valve 80 functions to engage the clutch |3 according to thedepression of the accelerator 14 when the valve 8| connects the conduits|10 and |52 and when the valve '83 connects the conduits |54 and |12.When the accelerator is depressed, the lever |40 is rotatedcounterclockwise, as has been described, and this movement istransmitted through the link |63 to the plunger |59. The plunger |59moves to the left as seen in Fig. 2 and moves the valve piston |55 alsoin this direction. Movement of the piston |55 in this directionfunctions to connect the conduit |54 through the chamber 53, thepassages |56 and the internal opening of the piston with the atmospereto relieve the vacuum on the motor 84 to engage the clutch. The motor|65 acting through the floating lever |68 acts to move the piston |55back to the right as the vacuum is relieved on the two vacuum motorswhich are connected through the chamber |53 in causing an engagement ofthe clutch I3, and a small movement of the plunger |59 to the left asseen in the gure thus causes only a small engagement of the clutch |3due to the action of the motor |65. all as Will be more fully describedbelow. The clutch I3 is fully engaged when the plunger |69 is movedsufficiently so that its stop |60 contacts the valve block and continuedmove- 'ment of the accelerator 14 thereafter toward its fully openthrottle position causes movement of the levers |48 and |42 about theconnection of the lever |48 with the link |63 and the lever |40 aboutthe pivot |48 to further open the butterfly valve 18. Y The vacuum motor85 is controlled by means of the Valves 81 and 88. The valve 81comprises a'valve piston A|85 actuated by the solenoid |21. 'Ihe valveis connected with a source of vacuum by means of a conduit |86 and withthe motor 85 by means of a conduit |81. In the deenergized condition ofthe solenoid |21, the valve piston |85 is in its position as shown andblocks the conduit |88. When the solenoid |21 is energized, the valvepiston |85 is raised and functions to connect the conduits |85 and |81for applying vacuum to the motor 85. The valve 88 is similar inconstruction to the valve 81, and the similarly numbered parts functionin the same manner as those in the valve 81; the valve 88 is, however,connected to the opposite side of the motor 85 and functions to energizethe motor in the opposite direction.

The motor 85 comprises a piston |88 which is acted upon by a pair ofsprings |89 and |99. The springs function to yieldingly maintain thepiston in its neutral position as will be understood. The piston is alsoacted on by the holding coils |29 and |38 when the piston is in eitherof its extreme positions, and these coils function to augment the forceof the vacuum acting on the piston and applied through one of the valves81 and 88. The piston is connected to a shift lever 9|, comprisinga'part of the lever and switch assembly 86, by means of a rod |92. Thelever |9| is swingably disposed on a shaft |93 which is rotatablydisposed in the transmission housing 35 in any suitable manner (notshown). A shift element |94 is fixed to the shaft |93, and the shaft |93has xed thereto on its inner end an element |95 carrying the fork 89which is disposed in the groove provided in the collar 55. Thearrangement is such that when the shift element |94 is moved, theelement |95 and the yoke 60 and collar 55 are given a correspondingmovement.

1 The shift lever |9| and the shift element |94 have a lost-motionconnection between them. This connection is provided by two lugs |98 and|91 disposed on opposite edges of the shift lever |9|. When the shiftlever |9| is moved by the motor 85, the shift lever does not function tomove the shift element until one of the lugs |98 and |91 contacts theshift element. The motor 85 is adapted to shift the shift element |94and the collar 55 only a portion of the distance required for themeshing of the internal teth of the collar 55 with the teeth 51 and 58,and the element |95 and the collar 55 are moved the remainder of thedistance required for full engagement by ball and detent means. The balland detent means comprises a ball |98 and a spring |99 disposed betweena stationary part 28|] of the transmission housing 35 and the ball.Grooves 29| are provided in the shift element |95, and the ball |98coacting with the grooves functions to move the shift element |95 andcollar 55 into fully engaged positions after the motor 85 has functionedto move the shift element |95 into position so that the ball and detentmeans may become effective.

" The switch |3| comprises a plunger 282 carrying the switch arm |33.The plunger extends 410 through the lug |91 and is reciprocable withrespect to the lug |91 and the plunger is acted on by the shift element|94. The switch is so arranged that when the shift lever |9| is acted onby the motor so as to take up the lost motion between the shift element|94 and the shift lever |9| the switch arm |33 is moved to contacteither of the switch contacts |32 so as to close the switch |3|. yOperation Vehicle at rest, with ignition switch open-In this conditionof the vehicle, the parts of the transmission and its operatingmechanism are as shown in Figs. 1 and 2. The transmission is in neutralcondition, and the gear 45 is in its outof-mesh position, in which it isshown in Fig. 1. The ignition switch 55 is open and none of theelectrical parts of the controlling mechanism are energized. The engine2 is inoperative, and there is no vacuum in the conduit 69. The conduit|69 is furthermore closed with respect to theA rest of the Vacuum systemby the valves 8| and 83, the solenoids |25 and |28 being .deenergized Novacuum is therefore exerted on the motor 84, and the clutch I3 isengaged due to the action of the clutch springs 24. The two springs |89and |98 hold the piston |88 of the vacuum motor 85 in neutral position,and the shift collar 55 is in its neutral position.

Transmission conditioned for low speed forward, accelerator in closedthrottle position- This condition of the operating mechanism for thetransmission is shown in Fig. 3. In this gure, as in the followingfigures, various of the parts of the transmission operating mechanismare shown in positions differing from their positions shown in Fig. 2,as is apparent. In Fig. 3 and in the following gures the flow of currentthrough the various electric leads is indicated by showing these leadsin heavy lines and the exhausting of the various conduits as well as thesubsequent admission of air therein is indicated by appropriate arrowsshown in the conduits indicating the direction of the flow of airtherein.

- In order to condition the transmission itself for forward movement,the gear 45 is shifted to the left as seen in Fig. 1 to bring it intomesh with the gear 48. IThe ignition switch 65 is closed, and theforward direction switch 61 is also closed. 'lhe engine |2 is startedand is running in idling condition, and a vacuum is thus present in theconduit |69. Due to the closing of the ignition switch 85, the solenoid|25 of the valve 8| is energizecl to move the piston lll of the valveupwaroiy to close the conduit |52 to the atmosphere and connect it withthe conduit |10. A Vacuum is thereby caused to exist in the conduits |18and |52, in the valve 88, its chamber |53, the conduit |54, the valve 83and in the conduit |12 so that vacuum is exerted on the diaphragm |15 ofthe vacuum motor 84. The diaphragm |15 is thereby moved and is effectivethrough the link |16, the levers |11 and 21 and the clutch levers 28 topull the pressure plate I9 of the clutch i3 rearwardly to disengage theclutch. The valve 38 is conditioned lor operation by movement of thediaphragm of the motor |85 against the spring |66 due to the vacuumbeing exerted on the diaphragm through the conduit |61. This movement ofthe diaphragm of the motor |65 through the plunger |64 functions to movethe valve piston |55 to the left as seen in the gure to substantiallyalign its land |58 with theopenings |56 in the valve 80. The twodiaphragms |15 -11 and thatl of the motor |65 and the springs acting onthese diaphragms are so adjusted with respect to each other that thevalve piston |55 functions to substantially block the openings |56 whenthe clutch |3 is in fully disengaged condition.

Accelerator depressed for starting the vehicle-This condition of theoperating mechanism of the transmission is shown in Fig. 4. The vehicleis started by depressing the accelerator 14. The depression of theaccelerator functions through the linkage mechanism 11 to open thebutterfly valve 16 of the throttle 15 for increasing the speed of theengine |2. Such movement of the levers |40 and |42 of the linkage 11 hasthe additional function of causing movement of the plunger |59 to theleft as seen in the figure through the link |63, and for the present itis assumed that the accelerator has been depressed only enough to givethe plunger a small movement. This-movement of the plunger causes asmall movement of the valve piston |55 in the same direction. Thismovement of the valve piston operates to connect the motor 84 throughthe conduit |12, the valve 83, the conduit |54, the chamber |53, thepassages |56, and through the internal opening in the valve piston |55with the atmosphere for allowing a movement of the diaphragm |15 of themotor 84 toward the right as seen in the ligure with a resultantengaging movement of the clutch pressure plate I9. This decrease invacuum in these conduits and in the chamber |53 causes a correspondingdecrease in vacuum applied Vto the diaphragm of the motor |65 throughtheconduit |61 connected with the chamber |53. The diaphragm of themotor |65 thus has a small movement to the right as seen in the iigurewhich is caused by the spring |66 to thereby cause a small movement ofthe valve piston |55 in this direction. 'l'his movement of the valvepiston |55 again brings the land |58 of the piston over the passages |56to prevent a further decrease in the vacuum in the conduits |54, |12,and |61, and the clutch I3 remains in partially engaged condition. Itwill be understood that the clutch controlling valve |55 is controlledjointly by the plunger |59 and the plunger |64 through the agency of thefloating lever |68, and this movement of the plunger |59 in onedirection and of the plunger |64 in the other direction results in thereturn of the valve |55 to its initial position blocking the passages|56.

Further small movement of the plunger |59 to the left as seen in theiigure by means of the accelerator I4 thus causes a corresponding smallmovement of the pressure plate I9 of the clutch I3 toward fully engagedposition, and it will be apparent that the clutch I3 can be engaged asquickly as possible or in as many small different steps as desiredsimply by accordingly moving the accelerator 14 toward open throttleposition. This movement of the accelerator, it will be understood,causes corresponding movements of the buttery valve 16, and it will beapparent that an increasing amount of fuel is fed to the engine |2 bymeans of the accelerator at the same time as the clutch |3 is broughttoward fully engaged condition.

The lost motion between the link |40 and the portion |50 of the lever|42 is provided so that the clutch I3 is slightly engaged before thebutterfly valve 16 is moved from its engine idling position. Thisprevents the engine from being brought to a destructive or harmful speedbefore there is any engagement of the clutch. This slight engagement ofthe clutch is due to the fact that the plunger |59 is given a smallmovement before the valve 16 is moved by means of its linkage. rl'hegroove |62 is provided in the plunger for providing a direct connectionwith atmosphere from the chamber |53 when the plunger is moved to thelimit of its movement with the stop |60 contacting the valve block |5I.A release of vacuum on the vacuum motor 84 is thereby made quicker, aswhen the accelerator is moved quickly to fully opened position, inasmuchas the air in this case entering the chamber |53 and associated conduitsneed not all flow through the small passages |56.

When the plunger |59 is moved to the limit of its movement with its stop|60 contacting the valve block ISI, the clutch |3 is fully engaged. Thestop |60 makes such contact when the accelerator is approximately in itshalf open throttle position. Thereafter the lever |40 pivots about itsconnection with the link |63 and the lever |42 pivots about its pivotpoint |48, and the linkage 'i1 on further depression of the acceleratorfunctions to further open the butterfly valve 16 to further increase thespeed of the engine I2.

As is apparent from an inspection of the construction, tne greater thedecrease in vacuum in the conduits |54 and |12, the greater is theengagement of the clutch |3. In starting the vehicle, particularly incold weather, it frequently happens that the motor begins to stall.Under such conditions, the vacuum in the manifold of the enginedecreases, and there would be resulting decrease in the vacuum in theconduit |69 and thereby in the conduits connected therewith. .suchstalling of the engine would thus cause a further engagement of theclutch I3 and would increase the load on the engine whereby the enginewould be certain to completely stall. 'ihe one-way Valve 32 is providedIor preventing this increase in engagement of the clutch I3 when theengine starts to stall. When there is such a decrease in vacuum in theconduit |69 due to stalling of the engine, the valve 82 closes andmaintains the vacuum in the conduit |10 and the conduits connectedtherewith at the same high value as before the stalling to maintain theclutch I3Y in the same condition of disengagement as previously. Whenthe engine again begins to operate normally, the valve 82 reopens inresponse to the increase of vacuum in the conduit |69, and the operationof the clutch |3 under the control of the valve proceeds as has beendescribed.

When he clutch I3 has been thus engaged, the driven shaft II is drivenin low speed ratio, the gear train of which has previously beendescribed. Since the gear train includes the oneway clutch 41, this lowspeed drive is a freewheeling drive.

Vehicle traveling above five miles per hour, accelerator released toopen throttle position to upshift transmission to second speed-Thiscondition is shown in Fig. 5 of the drawings. An upshift from firstspeed to second speed ratio is obtained by releasing the accelerator 14and allowing it to return to its closed throttle position under theaction of the springs |2I and |49, after the speed of the vehicle hasreached ve miles per hour. At ve miles per hour speed of the vehicle,the governor contacts ||0 close and the governor contacts |09 open, ashas been described. Such opening of the contacts |09 breaks the electriccircuit through the solenoid |25 for the valve 8|, and the valve piston|1| returns to its position blocking the conduit |10 and opening the "13conduit |52 to atmosphere. After such movement of the valve piston |1I,the clutch I3 cannot thereafter be disengaged due to the action of theaccelerator 14.

When the accelerator returns to its closed throttle position, thecontacts I|4 are closed by the switch arm I|9 carried by the acceleratorplunger II1. An electric circuit is thus completed from the battery 88through the switches 95 and 61, the winding |89 of the relay 89, thecontacts II4 of the accelerator switch 13 and the contacts III! of thegovernor 12 to ground. The relay 89 is thus energized and its contactsI8! are closed and complete a circuit from the lower end of the winding|09 to the governor contacts ||8 and from thence to ground, this circuitbeing in parallel with that through the contacts ||4 of the acceleratorswitch 13. Thus after the contacts I4 are once closed by movement of theaccelerator 14, the relay 69 remains energized regardless of thesubsequent depression of the accelerator. The contacts |82 of the relay69 are closed when the relay is energized and they complete a circuitfrom the battery through the switches 85 and 51, the contacts |92, thecontacts 91 of the relay E8, the solenoid |21 and the holding coil |29to ground. The solenoid |21 is thus energized to control the valve 81.

Upon the solenoid |21 being thus energized, its valve piston |85 ismoved upwardly to effectively connect the associated conduits |86 and|81 and apply vacuum to the left side of the piston |88. The valve 88remains in its original condition and the other side of the piston iseffectively connected with the atmosphere. Such application of vacuum onthe piston |88 causes the piston to move toward the left as seen in thefigure and to thereby pull the shift lever |9| in a clockwise direction.The lug |91 of the shift lever makes contact with the shift element |94|and exerts a pressure on the shift element tending to move the shiftelement |94 and the collar 55 to engage the collar with the teeth 58 ofthe gear 43. During the initial movement of the shift lever |9| in aclockwise direction, it moves relative to the collar 55 and shiftelement |94 until the lug |91 strikes the shift element |94. When thelug |91 strikes the shift element I 94 the switch |3| is closed, andremains closed until the ball |98 functionsto shift the collar 55 intoits completely engaged position.

The switch |3| functions, during closure thereof when such a force isexerted on the shift lever |9| to cause a disengagement of the clutch I3and an incidental closing of the throttle by means of the butteriiyvalve 18. As has been described, the switch |3| is closed when the shiftlever |9| is so acted on by the motor 85 to tend to cause a shift of thecollar 55. The switch |3| completes a circuit through the solenoid |29for the valve 83 from the ignition switch 55, and the switch |3| alsocompletes a circuit from the ignition switch through the solenoid 19 forthe buttery valve 18. The energization of the solenoid |28 causes thevalve piston |14 of the valve 83 to move upwardly and connect theconduits |13 and |12. Vacuum is thus exerted on the diaphragm |15 of themotor 84 through the conduits |13 and |12 to disengage the clutch I3.Energization of the solenoid 19 acts on the armature |24 of the solenoid19 and rotates the buttery valve 18 to engine idling position, and thevalve 18 remains in this condition as long as the switch |3| is closed.While the motor 84 by means of the switch |3| thus functions todisengage the clutch |3 and bring the speed of the engine I2 to idlingcondition, the motor 89 functions to move the collar 55 into engagedcondition with the teeth 58 of the gear 43, with a synchronizer 59functioning to synchronize the speed of the collar 55 and the gear 43before a full engagement of the collar with the teeth. The disengagementof the clutch I3 allows an easy engagement of the collar with the teethand an easy functioning of the synchronizer, and the action of thebuttery valve 18 is such that the engine l2 cannot be increased toharmful speed while the clutch is disengaged regardless of the fact thatthe accelerator 14 may be depressed after the shift has once beeninitiated. Vehicle speed above five miles per hour, upshift to secondspeed ratio completed, dfmelerdtmn still released- This condition of thecontrol mechanism is shown in Fig. 6. As has been described, the motor`is effective for shifting the collar 55 through the greater part of itsshifting movement, and the ball and poppet means comprising the spring99 and the ball |98 is eiective to complete the shift. When the ball andpoppet means functions in this manner, the shift lever |9| and the shiftelement |94 move back to their original relative positions in which thelugs |98 and |91 are out of contact with the shift element |94. When theshift lever and the element have such relative movement, the switch ISIopens, inasmuch as the condition of the switch |3| is dependent upon therelative positions of the shift lever and the shift element. Suchopening of the switch |3| opens the circuit through the solenoid 19 forthe buttery valve 18 in the throttle 15 and also the circuit for thesolenoid I 28 for the valve 83. The butterfly valve 18 returns to itsthrottle opening position and the amount of fuel thereafter flowingthrough theithrottle 15 to the engine is dependent only on the positionof the butterfly valve 16 closed mechanically from the accelerator 14.-When the solenoid |28 of the valve 83 is deenergized, the valve piston|14 returns to its position blocking the conduit |13 and connecting theconduit |54 with the conduit |12. Vacuum is thus released on thediaphragm |15 of the vacuum motor 84 and air fiows through the valve 8|,the conduit |52, the valve 80, the conduit |54, the valve 83 and theconduit |12, as is indicated by the arrows in the figure. The diaphragmthus moves to the right as seen in the gure and the clutch I8 is againengaged under the action of the clutch springs 24.

With the clutch I3 being engaged and the collar 55 being moved intoengagement with the teeth 58, the transmission is in second speed ratio.The gear 45 remains engaged with the gear 48 in this speed ratio;however, there is no drive through these two gears inasmuch as theoneway clutch 41 overruns. The piston |88 is held in its illustratedposition by the holding coil |29, when the transmission is in this speedratio, and the holding coil functions in addition to the vacuum appliedon the piston |88 through the valve 81 to hold the piston in itsillustrated position. Therefore, even if the vacuum momentarilydecreases, the piston nevertheless remains in its illustrated positioncorresponding to second speed ratio.

Vehicle speed above five miles per hour, accelerator depressed, aftershift to second speed ratio- This condition of the control mechanism isshown in Fig. '7. The clutch I3 remains engaged and the motor 84 for theclutch remains in communication with the atmosphere. Theacaeeasoscelerator 14 in being depressed moves the plunger |59 of thevalve 86 to the left as seen in the figure to disconnect the conduit |52with the chamber |53 of the valve; however, the conduit |54 and thechamber |53 remain in communication with the atmosphere through theinternal opening of the valve piston |55 of the valve 3S. The depressionof the accelerator also changes the condition of the accelerator switch'1"3. The contacts ||4 are open, and the current therefore ceases toflow through the contacts; the rela-y 69 is, however, continued inenergized condition by means of the circuit through the conta-cts il ofthe relay and the contacts H of the governor l?.

The contacts of the accelerator switch 'i3 are closed by the depressionof the accelerator and as a result the relay 1D is energized. The switcharm i9 on a depression of the accelerator plunger ||1 completes acircuit across the contacts |55, and a circuit is thereby completed fromthe ignition switch 65 through the switch 5"?, the contacts |02 of therelay 5S, the winding |53 of the relay and the contacts i5 oi theaccelerator switch 'I3 to ground. The relay lil is thus energized toclose the contacts I and |55 of the relay. Closure of the contacts Hificompletes a circuit to ground through the winding H33 of the relay whichis in parallel With the circuit from the winding through the contacts|I5 of the accelerator switch 12. rThe relay l0 thereafter thus remainsenergized regardless of Whether or not the accelerator is so moved as tobreak the circuit between the contacts H5. Closure of the contacts |05of the relay 'I' conditions a circuit through the winding 96 of therelay 68 for energization by the accelerator switch 13 as will bedescribed. During energizaticn of the relay 19 by movement of theaccelerator, the transmission remains in second speed ratio, and theshaft Il is driven through the clutch and gears as has been A described.

Vehicle speed above ten miles per hour, accelerator moved to closedthrottle position to shift from second to third. speed ratios-Thiscondition of the transmission control mechanism is shown in Fig. 8.Above ten miles per hour speed of the vehicle, the contacts of thegovernor 12 are closed. These contacts are in series with the contactsH6 of the accelerator switch, and these two sets of contacts complete acircuit from the ignition switch 65, through the switch B'i, the winding96 of the relay 68, the contacts |55 of the relay 10, the contacts |06of the switch 1|, the contacts l I3 of the accelerator switch 13, andthe contacts I|| of the governor 12. The relay 53 is thus energized, andthe contacts 93 and 99 of this relay are closed while the contacts 51 ofthis relay are opened. Closure of the contacts 98 complete an additionalcircuit from the bottom of the winding 9S of the relay 68 to thecontacts ||6 of the accelerator switch '53 which is in parallel with thecircuit from the winding 9G through the contacts |05, the contacts |36and the contacts ||3 to the contacts H6. By means of this additionalcircuit, the relay 55 is continued in energized condition regardless ofwhether or not the accelerator is depressed to open the contacts |3after the relay 58 has once been energized.

Opening of the contacts 91 of the relay 58 has the effect of breakingthe electric circuit through the solenoid |21 for the valve 81 anddeenergizing the holding coil |29. The valve piston |65 of the valve 81thus returns to its original position blocking the associated conduit|86 and connecting the associated conduit |81 with the atmosphere. The

springY may then be effective to move the piston |38 to its neutralposition. Closure of the contacts S9 of the relay G8 has the ei-Tect ofcompleting a circuit from the ignition switch S5 through the switch 5land the contacts 98 to the solenoid t28 and through the holding coil 36.This encrgization of the solenoid 28 causes the valve piston 265 of thevalve B8 to move to its upper position and connect the associatedconduits |35 and |61 while disconnecting the conduit |31 from theatmosphere. Vacuum is thus applied to the right hand end of the piston|88 and functions to move it toward the right as seen in the figure.

The force exerted on the piston |33 by the spring' |9D and by the vacuumtending to move the piston toward the right as seen in ie figure causesthe lug or" the shift lever |9| to contact the shift element |95, andthis change in relative position between the shift lever ISI and shiltelement it causes the switch 13| to be closed. The switch |32 whenclosed functions in the same manner as has been described in connectionwith the upshift from first to second speed ratio, which is illustratedin Fig. 5, to energize the solenoid |25 of the valve 83 and energize thesolenoid 19 connected with the butterfly valve 18. This energizati'on ofthe solenoid |25 causes the valve piston |14 to move upwardly andconnect the conduits |`i3 and |12 for thereby applying vacuum to themotor 84, and the motor is then effectiveto disengage the clutch |3. Theenergization of the solenoid 19 functions to move the valve i8 to anengine idling position, so that the engine I2 remains in this conditionregardless of whether the accelerator is depressed or not after theshift has once been initiated. With the clutch i3 beingdisengaged andthe engine being maintained in idling condition, the spring |90 and thevacuum exerted on the opposite side of the piston |88 causes the shiftlever to shift the shift element in a counterclockwise direction todisengage the collar 55 from the teeth 58 and to engage the collar withthe teeth 5?. The syn chronizer 5e between the collar 55 and teeth 51 iseffective to synchronize the speed of the collar and the teeth prio:1 toengagement thereof, and such engagement is easily performed since theclutch i3 is disengaged. yThe transmission is now conditioned for thirdspeed drive. The piston |83 is heid at the limit of its movement to theright by the holding coil |30 as well as by the vacuum applied theretothrough the valve 88. The switch |3| opens when the collar 55 is fullyengaged with the teeth 51 due to the action of the ball and detent meanscomprising the spring |99 and ball |98, and the solenoids |26 and 19 arethereby deenergized. The deenergization of the solenoid |26 actuates thevalve 83 to reengage the clutch, and the deenergization of the solenoid19 causes an opening of the butterlly valve 13 so that the openingthrough the throttle 15 is thereafter solely under the control of theaccelerator 14. The solenoids |26 and 19 function to engage the clutch i3 and open the butterfly valve 'i8 in the same manner as in a shift fromrst to second speed ratio as is illustrated in Fig. 6. The gear remainsengaged with the gear 48 in high speed ratio; however, the one-wayclutch 41 overruns, and there is no drive through these gears.

Vehicle speed above ten M. P. H., accelerator depressed to open throttleposition to downshijt the transmission from third to second speedratifica- This condition of the operating mechanism of the transmissionis shown in Fig. 9. The

accelerator 14 in its depressed open throttle position functions withthe remainder of the operating mechanism to downshift the transmissionfrom third speed ratio to second speed ratio, as when it is desired bythe operator to obtain a high torque for passing another vehicle on theroad, for example. It is to be noted from Fig. 8 that the relay 68 iskept in energized condition by means of a circuit through the contactsHS of the accelerator switch 13. When the accelerator 14 is depressed toopen-throttle position, the switch arm |20 is moved against the actionof the spring |22 by means of the accelerator plunger I I1 to break thecircuit through the contacts I |6, and the relay 68 is thus deenergized.Deenergization of the relay 68 has the effect of opening the contacts 98and 99 of the relay and of closing the contacts 91 of the relay.

Opening of the contacts 99 of the relay 68 has the effect ofdeenergizing the holding coil |38 and deenergizing the solenoid |28 cfthe valve 88 and .returning the valve piston of the'valve 08 to itsposition in which it closes the vacuum conduit |86 connected with thevalve and opens the associated conduit |61 to the atmosphere. Closing ofthe contacts 91 of the relay 08 has the effect of completing a circuitfrom the ignition switch G5 through the switch 61, the contacts |02,`the contacts S1, to the solenoid |21 and the holding coil |29. The valvepiston |85 of the valve 31 is moved by energization of the solenoid |21to disconnect the associated conduit |81 with the atmosphere and toconnect the associated conduits I 66 and |81 together. Due to thesechanges in condition of the valves 81 and 80, the spring |89 iseffective to move the piston |88 toward the left, and the vacuum exertedon the piston through the conduit |01 connected with the valve 81 isalso effective to move the piston in this direction` It will be notedthat the other relays 60 and 10 remain in their energized conditions, as.they were prior to the kickdown by the accelerator. The piston |88exerts a force on the shift lever IS! tending to move it in a clockwisedirection, and the lug |91 of the shift lever contacts the shift element|94. On such change in relative positions of the shift lever and shiftelement, the switch I 3| is closed, as has been described, and theswitch completes electric circuits through the solenoid 19 for thebuttery valve 13 and through the solenoid |26 for the valve 83, Suchenergization of the solenoid 19 closes the butterfly valve 18 to engineidling position, and such energization of the solenoid |26 raises thepiston |14 to disconnect the conduit |12 with the conduit |54 and toconnect it instead with the conduit |13. The valve 83 is thus effectiveto apply vacuum to the motor 84 for disengaging the clutch I3. As isapparent, the switch I3! when closed is effective in the same manner asin an upshift from low speed ratio to second speed ratio which has beenheretofore described and is illustrated in Fig. 5.

rihe clutch I3 is disengaged and the engine I2 has been reduced toidling speed, regardless of the fact that the accelerator 14 is in openthrottle position, as has been described, and the piston I B6 is theneffective to shift the shift lever 59| and collar 55 to engage thecollar with the teeth 53. The synchronizer 59 between the teeth andcollar acts as before to synchronize the speed of the collar 55 andteeth 58 before engagement thereof. When the piston |88 has completedits stroke, the spring and poppet means including the ball |98 andspring |99 is effective to complete the shift of the collar, and in sucha completion of the shift, the switch |3| is opened. Such opening of theswitch deenergizes the solenoid |26 for the valve 83 and also thesolenoid |19 for the butterfly valve 18, and the drive is then throughthe transmission in second speed ratio with the clutch I3 being engagedand the throttle 15 being completely under the control of theaccelerator 14.

The forty mile per hour contacts ||2 of the governor 12 are effectivefor preventing a kickdown from third speed ratio to second speed ratioby means of the accelerator when the vehicle is traveling above thisspeed. 'Ihe contacts I2 connected with ground. it will be noted, are inparallel with the circuit including the contacts ||6 of the acceleratorswitch 13 and the governor contacts Therefore, it will be apparent thatan opening of the contacts ||6 by a depression of the accelerator 111when the contacts I2 are closed can have no effect in deenergizing relay68 for shifting from third speed ratio to second speed ratio. Thegovernor contacts |2 thus advantageously operate to prevent a downshiftabove the speed at which a downshift would not produce any substantialincrease in torque and would allow the engine |2 to attain destructiveor harmful speeds.

The coast switch 1| is effective when moved from its position as shownin the drawings connecting the contacts |06 to its lower positionconnectingthe contacts |01 to prevent an upshift from second speed ratioto third speed ratio or to downshift the transmission to second speedratio if it is in high speed ratio. This switch is useful when thevehicle is descending a steep grade at which time it is desired to usethe engine I2 as a brake for the vehicle. As has been described inconnection with Fig. 8, the circuit for energizing the winding 96 of therelay 63 for shifting the transmission from second speed ratio to thirdspeed ratio includes the contacts |05, the contacts |06 of the coastswitch 1|, the contacts ||3 of the accelerator switch 13, the contacts||6 of this switch and the governor switch By moving the switch 1| fromits illustrated position to its position connecting the contacts |01,this circuit is broken, and a release of the accelerator 14 cannotfunction to shift the transmission into high speed ratio. The switch 1|in connecting the contacts |01 functions to energize the relay 69 and tomaintain it energized. As has been described in connection with Fig. 5,the energization of the relay 69, when the relay 68 is deenergized,causes a shift of the transmission to second speed ratio, a circuitbeing completed from the ignition switch through the forward directionswitch 61, the contacts |02 of the relay 69, the contacts 91 of therelay 68, the solenoid |21 of the valve 81 and the holding coil |20. Ashas been described in connection with the latter figure, the upshiftfrom first speed to second speed is ordinarily made by a circuit fromthe ignition switch including the forward direction switch 61, thewinding |00 of the relay 9, the'contacts H4 of the accelerator switch 13and the contacts ||0 of the governor switch 'Filz however, the coastswitch 1| in connecting the contacts |01 accomplishes this function ofenergizing the relay 69 simply by grounding the winding |00 of therelay, and it is not necessary to connect the contacts ||4 of theaccelerator switch 13 by bringing the accelerator to a closed throttleposition.

T19 In, order., to. shift Jthe-transrnissionv interreverse the. gear'45' is'simply shifted-'from-its neutral .position in which itis shownAin Fig. 1 rearwaidly to interengage its-teethiwithther-teeth T52l of.the element'5l splined onthe driven'shaft IL". In so moving the gear45, itis also'brought into mesh with'itheiidler gear 5D. "The forwarddirection switch 61 is also. opened, -and "this Vhas .the effectof'maintaining'deenergized all of the .relays 68, s'and :'10andtheeassociatedeelectricalcircuits. -When` the'vehicle is running inreverse' drive,v therefore, theshiit-leverll is not shifted bythe'moto'rf-BS, inasmuchfasneither of the solenoidslZT and|28is'at'anytime en- ;ergized." The solenoid "|25 is'energized throughAthe governor contacts -|09 when-*the vehicle-'speed is 'less than ve`miles'per-hour in reverse-drive whereby-the'valve 8| connects theconduits-|10 The clutch I3 is thus-engaged and disengageckunder the.control -'of the accelerator '.14 in reverse "drivex in; the' same`rmanner as in forward drive.

.'Modzfiedtransmission control system A modified `transmission*'control-system is shown in Fig. l'O'in-the conditiorrin which it is With'theaccelerator depressed toopen-throttle position. Ithas beenfound'incertain embodiments* of the'transmission control systemin itsforminwhich it is'shownin Figs. 2 to 9 that if Athe conduits ISB-and|81l are too small' in di- `ameter, the springs |89" and |90 act soquickly "that the vacuumbn the'piston did not be- ".:comeL effective intimeto' maintain the switch |3| :closed fortheientire movement of thepiston from "its: second speed-'ratio positionA to its third speed'ratio position orvice versa.' vThis resulted in an engagement'of'theclutch' |3vbefore the'shift'was I ,10, has been designedto 'obviate`thisk difficulty, fwithout changing*theiconduits |86 and |81 or thesprings |88 and |'9Din any way.

" The change of vthe-Fig. embodiment over thatshown in Figs. 2 to 9comprises .the addition :of a switch2|0 actuatediby the vacuum motor 85.

' The'switch 2| il comprises a: pivotally mounted `switch arm 2| l.having a'pin and slotconnection 2|2 .withthe link |92. The switch arm2|| is an electric'conductor and cooperates with a contact .2|3'inthe'formof'an are. The arc 2|3'is continuedV on its'ends by portions 2|4.which are of nonconducting material.V The switch arm 2|| is connectedwith oneof the contacts l I4 of the accelerator switclrlgand'the'contact 2| 3 of the switch is connected" with the contacts |32 ofthe switch "|3l. .As is apparent, the'switch 2|0 is closed whenthe'piston `|58 is'in neutral position and` is Yopen when the piston`|88 is'in either of its positions'providing vthe second 'or third speedratios. through' the transmission.

.lifterl the't-ransmission has been shifted from second tothirdspeedratio and the accelerator is depressed to'downshiftthetransmission, the control mechanism is`in the condition in which it is'shown'in Fig'. 10,*"assuming that thel spring |89 1 has acted beforethevacuum has had effect on the piston 'to move the shift lever 19| toneutral-position. i VInthis condition of the mecharnism, the ball anddetent means comprising the *the shift element-|94 to its neutralposition, so

kthat the switch 13| is open. In this case, the solenoid |26 Aforthevalve 83 and the solenoid 19 for the buttery valve 'I3 are maintainedenergized, so that the engine is held in engine idling an` opening'ofthe switch' |3|.

" mission" is kbeing :upshifted from-'second vspeed ratio to third*speed ratio, -the switch 2 0 functions inthe samey manner to completecircuits through the solenoids -TS' and |26 for maintaining .the clutchI3 disengaged and the throttle valve 'I8 closed during the shift.

We wish it to be understood that ourinven- 'tion is vnot to be limitedlto the specific constructions'and arrangements shown and described ex-Vceptonly insofaras the claims may be so'li'mited, .as it willbeapparent tothose skilled in the 'art :that changes may be madewithoutdeparting from the'principles of theinvention.

We claim:

l. In .transmission mechanisnrthe combination'of a drive shaft, a drivenshaft'fgearing for providing a plurality of'speed ratios between saidshafts and including a positive type clutchv for establishing one of.the lspeed ratios, a friction clutch` connected to said drive shaft, apower cylinder for shifting said positive type clutch, power mechanismfor disengaging said friction'clutch.

.and a lost motion switch actuated by said power `cylinderand.putinto achanged electrical. condition .when the power cylinder is operative toshift the positive. clutch,said switch being connectedv w-thsaid powermechanism to cause a disengagementofisaidfriction clutch whensaid powercylinder is operative for shifting said positive clutch.

2;.vIn transmission.. mechanism, 4the combination.of a-drive shaft,adriven shaft, gearingfor ...providing avplurality of speed ratiosbetween said y.shaftsand including a positive type clutch forestablishing one of thev speed ratios, a friction Cil .'.clutch.connected Ato saiddrive shaft, a power cylinder for shifting saidpositive clutch and connect'ed to the positive'clutch by means of twolevers. having a lost `motion between the levers,

. power mechanism .for disengaging said friction clutch, and switchmeans actuated by said levers rand put into a changed electricalcondition when "the power4 cylinder isoperativeto shift the positiveclutch, said switch means being .connected with said power. mechanism tocause a disengagement of said friction clutch when said power cylinderlisoperative for shifting said positive 3. In transmission mechanism, thecombination of a drive` shaft, a driven shaft, gearing for providingaplurality of .speed ratios between said .shafts and including apositive type clutch for .establishing one :ofthe speed ratios,afriction `clutch connected to said drive shaft, a power cyl- '..ihderforshifting'said positive clutch and connected with'the positive clutchby means of a 1 lost motion'connectiom'said Vconnection comprising alever connected with the power cylinder,

a second lever connected with said positive clutch andanabutment`meanson said first lever contacting said second lever after the first leverhas y"moved a predetermined' distance, power mechanism for disengagingsaid friction clutch, and an electrical switch connected with saidlevers

